Saturday, April 23, 2011

One last short post, just to give a bit of significant news in the world of cycling.

It is significant in that it boosts the efforts of the biological passport even further, and it is significant because it follows on from a series of posts we did just over a month ago on the biological passort, its scientific and legal issues.

That news is that Tadej Valjavec has been banned for two years on the basis of the athlete biological passport system. The ban is an overturning of an earlier Slovenian decision to clear the rider.

Some articles summarizing the Valjavec ruling can be found here and here, and they explain how the passport has received yet another boost as a result of this decision. This follows on from the CAS decisions to uphold the ban of Pietro Caucchioli and to overturn a CONI decision to exonerate Franco Pellizotti in early March. The second decision in particular was significant, because CAS ruled against the Italian federation that had cleared Pellizotti despite biological passport figures that were deemed suspicious.

The same has now happened for Valjevic - he was initially cleared by the Olympic Committee of Slovenia, on the basis that he argued that his suspicious values (strikes, as we called them in our series) were the result of an ulcer. His case was apparently very well presented, with some serious "heavy-weight" experts arguing it out before the CAS. This was therefore the most stringent legal test of the passport to date - we discussed in our articles the legal issues, and the chances of "false strikes" against riders. Valjevic tested that system to its limit, and it came out stronger, and that's a great step forward for the passport system.

CAS said in a statement that "The CAS has set aside the decision of the OCS to exonerate the athlete from any doping offense and has imposed a two-year ban on him starting on 20 January 2011, as well as the disqualification of all his results obtained between 19 April and 30 September 2009 and a fine of EUR 52’500".

Every one of these cases strengthens the legal basis and adds momentum and "clout" to the biological passport system. CAS used the precedent set in the Caucchioli and Pellizotti cases to make this ruling, and further cases like this are likely.

Our articles on bio passport, which include some great discussion, including inputs from those scientists who are actually responsible for the passport's creation and implementation (for which we are enormously honoured) can be found here:

All in all, the passport may not be perfect, and yes, athletes will micro-dose and get away with doping, but as we showed (in Part 2 of the series), it's making a difference. And now the CAS are supporting that effort and adding weight to it.

Boston was "not excessively aided" say the ARRS. But their conclusion has (major) problems...

We hope everyone is enjoying a timely Easter break. Having wrapped up Boston in my previous post, I received a few emails and comments about another analysis of Boston, and thought I'd comment briefly on it here rather than in the discussion thread to previous posts or on Twitter!

Writing in this week's "Analytical Distance Runner," the official ARRS publication, chief analyst Ken Young wrote: "It should also be noted that Geoffrey Mutai (KEN) who ran 2:03:02 (in Boston), was ranked #2 on the ARRS competitive rankings and he had been ranked #1 for four weeks earlier in the year. When Haile Gebrselassie (ETH) set the current world record of 2:03:58.2, he was ranked #10 in the world. Hence, it is not surprising that Mutai could be capable of significantly bettering the world record. Too bad that he ran this on a course that is not eligible for records."

So they are estimating an improvement of 1:37 for the men, which is then apparently not significantly aided, this is judged according to criteria that anything improved by more than 5 seconds/km is considered excessively aided.

Very quickly, some thoughts on this to fill the Easter weekend break!

Using ranking to justify times

First off, the astonishing statement is that Mutai would be expected to significant break the record because he was ranked first in the world, compared to Gebrselassie who was ranked tenth when he broke 2:04. Well, perhaps they've forgotten that Gebrselassie was already the world record holder. And that was only one year earlier! So they can take that 10th ranking and lob it into a trash can, because he was only 26 seconds off the 2:04 barrier when he stood on the start-line, a year earlier, and therefore was totally expected to have a shot at beating the time. Which he did, by 29 seconds.

Now, they're suggesting that a man ranked number 1 (and make no mistake, Geoffrey Mutai is pedigreed, and has "WR holder" written all over him), should break a record by 58 seconds given that his previous best was 56 seconds off the old one, but that he was ranked # 1...

That's poor inference if ever I have read it.

"Not excessively aided"? The 5 sec/km implication

The next big claim in the article is that they estimate an improvement of 1:37 which they suggest is not excessively aided. Granted, that's their estimate of how much Mutai benefited, and one can argue that he naturally achieved this leap in performance (I'd argue very strongly against this), but there are a couple of issues.

First, the overall conclusion (and heading of the article) is flawed because 1:37 is a big difference to make if that is their estimate. To illustrate, it takes the time from being greatest ever by almost a minute, to making Mutai only 6th fastest performer in history, so I don't know how they arrived at "not excessively aided"...it's a huge difference.

The thing about that is they've set what is a very poor (and possibly arbitrary) cut off for "excessively aided" at 5 sec/km. I am not sure why they've chosen this size, but when was the last time we saw the marathon world record bettered by 3:30? (I can tell you the answer - it was Jim Peters in 1952).

And if we did see a WR beaten by 3:30, what would our reaction be? "Measure the course again", I suspect! Imagine the 10k WR going from 26:17 to 25:27 in one run - we would think the guys had miscounted the number of laps and done 24 rather than 25! The 5,000m record improved by 25 seconds? When Gebrselassie broke it by 11 in 1995 is was staggering.

Now granted, I'm not sure whether the ARRS would apply their 5 sec/km principle to these events, but I'm illustrating the point - in a competitive sport with long history and access, performances at the level of a world record, in any event, are not improved by that kind of margin, ever. The marathon world record will not fall by more than 3 minutes. (Of course, it's possible that the record in some trail run or small event is broken by the amount, but the key is the "strength and depth" of the event, which is a function of how many people do it, over how long and what quality they are. The marathon is solid, it's too strong and too old for "weak records")

So while interesting, I think they have lost sight of the wood for the trees. The first mistake is to look at the depth of the field, when really, the issue is the top, top level of runner. The first five to ten men tell you what really happened, and they are the men who DO NOT improve by 5 seconds/km when already at the WR limit. As I said, the WR in the marathon has not leaped forward by 5 sec/km in almost 60 years.

In fact, since Dinsamo's record of 2:06:50 was bettered in 1998, SIX world records have been set, and the AVERAGE improvement has been 28.3 seconds. That's 0.7 sec/km. So a 5 sec/km margin might be fine for the masses, or even the near-elite, but for men trying to run faster than any human in history, 5 seconds per kilometer is, frankly, ridiculous. And that's why a 1:37 "aiding" is massive!

As mentioned, this is the result of the method they use, which I don't think is very sound to answer this question. That is, don't look at 43 elites, look at the very best in relation to the very best in previous years. So take a look at point 7 in this Letsrun.com recap of the week (the whole article is worth reading, in fact), because it presents that the wind had a very meaningful effect. A record that stood for many years (from 1994) is bettered by Robert Cheruiyot, then bettered again in 2010, and then suddenly, seven men are faster than that, five of them by more than a minute. That's excessive, in performance language, no matter what "stats" suggest.

The issue with statistics and meaningful differences

This is a classic case of whether statistical significance is more relevant than what is meaningfully different. A lot of times in sports science research, studies will use statistical methods to conclude that a treatment or method (say for example altitude training) is not beneficial because it results in an improvement of say 15 seconds over 5,000m compared to a control group that for example did sea-level training. And sure, there's a chance that these 15 seconds are down to 'chance' and thus not significant. But equally, any elite athlete will tell you that "IF" they can find a 15 second improvement, they'll take it. Most athletes will take an improvement of 5 seconds over 5,000m at the level of Olympic contender, because that's the difference between podium and back of the pack!

So there's a new method of statistics for sports science studies (and others, of course) where you now look for meaningful differences between groups. And I can pretty much guarantee that a 1:37 improvement for an athlete who was already at 2:05 is going to be a meaningful difference. Was it just a great day? Was it the wind? I've expressed my view that at that level, the margins are seconds, not minutes, and so I think the wind had a big effect.

However, as we've said before, Berlin and Chicago will tell us, because if Mutai and Mosop are in the same shape there, well, let's expect at 2:03:00 again...but until then, I believe the statisticians are missing something!

Thursday, April 21, 2011

First off, thank you so much for your great comments to the last post I did on the Boston Marathon and the possible effects of the wind on Mutai's amazing 2:03:02. The reaction has been overwhelming - the comments equivalent of a phone ringing off the hook! As has become the norm, the discussion to the post is twice as good as the post, so thank you! I apologize if I haven't been able to answer all the posts - I do read them, but things are rather busy here in Cape Town with the build up to the Two Oceans Ultra-Marathon this weekend!

With hindsight, and with the great discussion we've had on that post, I'd say that the one thing I didn't account for enough in the analysis of the history of Boston is the tactical nature of the Boston race compared to the fast, paced races of London, Chicago, Berlin.

Given that factor, I'd probably revise my impact of the wind to about 2%, which would place it around 2:20 to 3 minutes. That would mean that Mutai was running mid 2:05 on the Boston course, which is perhaps a 2:04 or mid-2:03 pace anywhere else, and that of course is realistic for a man who is clearly among the best right now. And like Mutai, there are a few men capable of that, in theory, which is what makes the Fall season so intriguing.

But the effect is not as low as one minute, or nothing at all. Moses Mosop's coach, Renato Canova, has tried to explain the wind away, calling analyses "stupid speculation". It is of course in his interests to coach a man genuinely capable of a 2:03:06, but I found his analysis full of holes, including the use of runners who ran slower than their PB as "proof" that the wind had no effect. He then works out that on average, Boston 2011 was slower, and so the wind couldn't have had an effect.

This is completely nonsensical, because runners underperform relative to their best all the time - just ask Kebede in London. Or Makau. Or Lel. Or Gharib. Fact is, you set your PB over many races, as a result of the confluence of great training, great form, and a great day. And when you compare one race to a history of races (especially the marathon, where it's not difficult to go two or three minutes slower - again, ask Kebede and any other marathon runner), you will almost always end up with this 'answer'. Simply, there is too much variability in marathon running to make this analysis credible. Performing beneath your own ceiling is not evidence that an advantage doesn't exist, whereas exceeding the ceiling MAY mean it does.

There is also the very obvious oversight that not feeling a wind at all doesn't mean there is zero wind; it means it's a tailwind equal to the speed of running. Amby Burfoot observed this at the press conference, where most of the athletes said that they felt "no wind", which is perhaps the most telling observation of all.

There is also this justification that the wind switched around a lot and was sheltered by buildings. Of course it would be, but you don't need a tailwind for 42,195 to have an effect, and no one is basing the calculation on a 20mph tailwind the whole way. The physics calculations we showed assumed relatively low average tailwind of 14mph, equal, on average, to the speed of running. The photo to the right suggests that it was, at times, greater, and I'm sure it would be lower at others. But it was still a net tailwind, in the range of 12 to 18mph, and it had an effect.

In any event, the acid test will come later in the year. Let's see if Mutai, Mosop and even Hall are able to reproduce anything close to their Boston performances without the wind, even on flatter courses.

I thought I'd wrap up the Spring Marathon seasons though, and chat about the women's race, which was yet another one of the ages in Boston, and then look ahead to the Fall, and what may happen there.

The women's race, one for the ages

It got lost in the discussion about the wind, but yet again in Boston, the women's race produced a great duel all the way to the finish line. It was reminiscent of the Wanjiru-Kebede duel in Chicago last year, where those two champions surged and counter-surged in what was more like a bicycle race than a marathon finish! This time it was Caroline Kilel and Desiree Davila who raced it out. You can read our Live post here for the "play-by-play", surge by surge account of what was maybe the best race of the Spring marathon season

Neither would have been a recognized favourite before the race. Those went by the wayside very early - defending champion Erkesso was out of it within the first 20km, and then Dire Tune, maybe the big favourite, was dropped soon after 30km by a pace that, it has to be said, wasn't all that fast.

Then it was left to three. Sharon Cherop, Davila and Kilel. None had spectacular credentials - Cherop was the fastest with a 2:22:43 last year, while Kilel, aged 30, had a 2:23:44 to her credit. Davila, meanwhile, has been improving consistently, but with a PR of 2:26 would perhaps not have been expected to outlast those around her.

That she did though, and she was the aggressor for much of the second half of the race. In an amazing display of courage, she took the race to Kilel and Cherop and there were times when the elastic between her and the two Kenyans was stretched. But it never broke. Kilel was able to cover all the surges, and the three entered the final 2km together. Cherop would eventually be dropped, and Davila seemed to have run her race when a gap of 5 m appeared and Kilel seemed to be pulling away.

But Davila dug deep, caught up and then counter-surged one last time. It was spectacular racing, full of guts, but in the end, Kilel had answers and won by a margin of two seconds. Cherop was only four seconds further back.

It was the fourth time in a row that Boston has produced such an epic finish. The victory margins in the last four Boston races have been 2, 1, 3 and 2 seconds. Average margin of victory since 2008 is two seconds! And so if it's competitive racing you want, Boston seems to have something that produces it among the women.

The impact of the wind on the women

As for the times, collectively, the women ran faster than ever in Boston. Margaret Okayo's course record of 2:20:43 (2002) survived, but PRs didn't, and the depth of the fast times says a lot about the day. A few people have written in to say that the women's result suggests that the wind wasn't that bad, but here are some numbers:

The winner was fourth fastest in the history of the race - only Okayo's amazing run survived, along with Ndereba's, who was second that day in 2002, in 2:21:12. The third best time of Uta Pippig came in 1994, when the wind was blowing almost as strongly as on Monday. Some estimated that the wind that day was worth 3 minutes to Pippig

Davila's time was the fastest ever by an American woman

The top 5 all ran PBs - Kilel, at 30, and with 11 marathons in her resume, broke her PB by just under a minute. Davila hers by almost four minutes, Cherop by a few seconds, and then fourth was Caroline Rotich who set a new PB by about 5 minutes. Kara Goucher in fifth was over a minute faster.

And yes, one or two runners will always have great days, with breakthroughs or big improvements (because their previous best might have come from a tactical or hilly race like NY), but four out of the top 5 improved by margins rarely seen at this level. And key is that everyone was way faster in Boston compared to previous Bostons

Overall, the times were faster than ever. Davila and Cherop finished within six seconds of the winner, and so I believe the average of the top 3 was the fastest in history. The other super-fast run was in 2002, when Okayo broke the record. On that occasion, Ndereba ran 2:21:12 to finish second, but the third placer was a 2:26. This time, the top six broke 2:26 and so it was deep and fast

The other thing about the women's race is that it started very tactically. Kim Smith was almost a minute clear within 15km. By halfway, that lead was 50 seconds. But she wasn't really going that quickly - her split at the half was 1:10:52, and the main group was almost a minute behind with a dozen women in it. So there's no question that the women started conservatively, much more than the men, and the overall time reflects that.

And finally, I don't think this women's field is nearly as strong as what was seen the day before in London. Where would Kilel, Davila and Cherop ranked in a race with Keitany, Shobukhova and Kiplagat? If you say top 3, I'd challenge you on that. Simply put, this was not a super strong field, yet they ran times rarely seen in Boston. As a final word, the wheelchair races were also super quick. The women's course record was broken - the previous record, you shouldn't be surprised to learn, was set in 1994, the very windy year that saw both men's and women's course records. The men's race was the second fastest ever, and it came down to a three-way sprint.

Looking to the Fall - the anticipation builds

The upshot of all this (including the debate) is that we have a magnificent fall marathon season to look forward to. Two Mutais, one a winner in London, one in Boston. Emmanuel produced a 28:44 10km stretch to break a field that included Makau, Kebede and Lel. Geoffrey produced a 28:15, albeit wind-assisted to run a minute inside a world record. And so did Moses Mosop, for that matter, in his debut. Improvement with experience...?

Still to join the 2011 year is Sammy Wanjiru. Tsegay Kebede underperformed in London, but he'll be back, no doubt. The Berlin and Chicago races later this year will produce huge racing between what is now one of the deepest and highest quality groups of marathoners ever seen.

Will Boston 2011, 2:03:02 change those races? There is a school of thought that the mindset of the elite will be changed by this, that 2:03 is the new 2:04, and that they'll be more aggressive, more willing to go out in 61:00 to 61:30 for the half.

It will certainly be fascinating to see how the elites structure the races. There's no question that there are currently four or five guys who have the capacity to break the 2:04-barrier. Mosop, Mutai, Mutai, Wanjiru, Makau, Kebede. Plus one or two others who've not yet had the opportunity. Will they go out in 61:30, inspired by the belief that a 2:03 is possible? They may, but I doubt it. I think it's more likely we'll see the target at 61:45 to 62 at halfway, with the hope that one of these guys can hang on in a 62 to break the world record.

I'd love to see the 61:30 or so at halfway. My hypothesis at this stage is that if they do, they'll blow in the second half, and run a 63, at best, missing the world record. At that level, with things not being absolutely perfect, 1 second per kilometer too fast is, well, too fast, and so expect incremental changes, not the kind of radical leap that Boston produced. And speaking of perfect, it will need absolutely perfect conditions as well - too warm, too gusty, record gone.

Bring on the Fall!

Ross

P.S. And lastly, here are two videos from the race, showing women's top 3 at 300fps about half a mile from the finish line. Great footage at slow speed, and its interesting to note the mechanical differences between Davila, Hall and the Kenyans. Food for thought...?

Tuesday, April 19, 2011

2:03:02 dissected. What effect did the tailwind have? 3 to 4 minutes...?

I don't know the answer to that question. Let me say that right upfront. It's insoluble. But it's too intriguing not to ask, and attempt to answer, and there are a few approaches to it to shed light on a quite remarkable Boston Marathon, now that the wind has died down and the dust settled on the fastest two marathons in history. Just where do Geoffrey Mutai's 2:03:02 (and, for that matter, Moses Mosop's 2:03:06) rank in the history of marathon performances?

Not a recognized record - why not?

As you'll know, Mutai's record will not be accepted as the official world record. The main reason is that Boston is a point-to-point course with an overall drop in elevation greater than 1 m per kilometer, a one in a thousand drop (Boston drops by 135 m). Also, a second criteria for course eligibility is that "The start and finish points of a course, measured along a theoretical straight line between them, shall not be further apart than 50% of the race distance". This would apply to Boston, because the course is basically a straight line running north-east, and that is why a south-westerly wind, as we saw today, would have such a profound effect. The image below (click to enlarge), again taken from Letsrun.com in their preview, shows this nicely. The wunderground.com site had the wind at 14mph westerly, incidentally.

So not recognizing Mutai's time is indirectly influenced by the wind (as indicated by that second clause which would help to prevent a 'wind-aided' record), but it's mainly because of the drop, despite the fact that Boston is actually a slower course than the other Majors, as we'll see below. But the real meat of this debate is the effect of the wind on the times? And what would Mutai have run on any other course?

Let's repeat that this question is unanswerable. We will never know exactly what Mutai would be capable of on a flat, fast course like Berlin or Rotterdam on a still day. We will never be able to quantify the improvement that might have occurred thanks to the tailwind during today's race.

Equally, we will never know how much Boston's relatively tougher profile, with its Newton Hills in the second half, costs runners compared to the flat and fast courses in Europe and Chicago. So to ask "What could Mutai have run in Berlin?" is a rather futile exercise. I know this, and so this is somewhat speculative. But it's also an intriguing one, and there are some analytical approaches that one can take to help remove guesswork and rather be informed speculation! And that is the purpose of this post!

So, what effect did the wind have on Mutai, Mosop and co?

The mathematical approach - drag, wind resistance and improvement

I must confess this is not my first approach to the problem, but it is the best one. My first approach is physiology and the physiological variance in performance, combined with historical context, as you'll see below. But if you have the physics, then this approach brings some objectivity.

The two problems with this are that you need to make some assumptions about how to treat the runner - a cylinder with a given drag, and an assumed mass and height. Also, you cannot always know that the wind is from behind, and nor do you know its speed the whole way, so there are estimates, but I still feel you still get valuable information given the length of the course, provided you make valid inputs. It gets us into the ballpark.

So thanks to djconnel and Giovanni Ciriani for their inputs on this, which I'm pasting directly below:

Assume a human is 1.7 meters tall by 40 cm wide, with Cd close to 1 for a cylinder with normal wind incidence. That's CdA = 1.5 meters squared. Then assume the wind is blowing at around 2 m/sec (very fast for road-level given how fast these guys are running) with an air density near 1.2 kg/m-cubed. That's 6.25 N = 6.25 kJ/km. Minetti measured close to 3.4 kJ/km/km for running: http://jap.physiology.org/content/93/3/1039.full. So if a runner weighs 60 kg, that's 204 J/m, of which the tailwind is saving 6.25 J/m, which if speed is proportional to power, is 3.8 minutes saved. (courtesy djconnel).

So that's 3 min and 48 seconds.

And then there is this, the wind resistance and relative velocity argument:

Aerodynamic drag for a runner is about 3% of forces acting against him/her. Today's wind in Boston (according to wunderground.com) was 14 mph W to E, which is just about the same speed the top runners were running at. Therefore the runners didn't experience aerodynamic drag. Since their power output remained the same, a 3% advantage translates directly into a 3% higher speed, and a 3% lower time = 3 min and 36 sec. (Courtesy G. Ciriani)

I'm going to work with an engineer to see if it's possible to refine the assumptions a little and work towards a clearer understanding of the physics. However, we're in the ball park of 2 to 3%, 3 to 4 minutes. Now, let's compare that to performance variations.

I'm a big believer in history, as it applies to performance. That's both "institutional history" and individual history. Historical context is important, because it points to what should be expected in terms of improvements in performance. Outliers happen, yes, like Bob Beamon almost jumping right over the pit in 1968, but when this happens, there is often an explanation, or at least part of one. That's the value of context.

And so when you have an outlier, historical lessons become even more valuable. 2:03:02 is an outlier, because it's almost a full minute faster than the current record, and it was achieved on a course that is generally recognized to be slower than the other big city courses (with the exception of NY).

So the first way to examine the effect of the wind on Mutai's performance is to ask how large an outlier it is for the Boston course specifically? The graph below shows the winning times in Boston since 1990.

The average winning time, excluding today, is 2:09:20, and interestingly, in the last TEN years since 2000, it has been 2:09:30. Boston is one of the few major marathons where times have NOT plummeted in the last decade. If you would rather compare Mutai to the best ever in Boston, then the previous record, only one year older, is that of Robert Cheruiyot, at 2:05:52.

So Mutai is 6:18 faster than the average and 2:50 faster than the next best time in Boston's history (with the exception of positions 2,3 and 4 in the same race, of course!). It's important to start with Boston-comparisons only, because as we'll see shortly, Boston cannot be directly compared to London, Chicago or Berlin without some correction for Boston's hills and slower course. What is more, the top four today all bettered the previous fastest Boston time by a considerable margin, since Hall finished in 2:04:58 to claim fourth.

Clearly, the wind had a significant effect on today's times, unless you believe that Mutai is genuinely a 2:03:02 guy in Boston, and by extension, that Mosop is at the same level, two minutes faster than the next best ever. You also have to believe that Hall is a 2:05 or faster runner on a hilly course (which many feel doesn't suit him).

And remember, these are all Boston times, and the flaw in the argument becomes apparent when you consider how "slow" Boston is compared to other big city marathons, as shown below:

So Boston "expects" to be 3 minutes slower than the big European races (Rotterdam is as fast, incidentally - we just don't have the times going back 10 years), and 2 minutes slower than Chicago. Recall that London has been won in 2:05:10, 2:05:19 and 2:04:40 in the last three years. Berlin - 2:03:59, 2:06:08 and 2:05:08. Boston? 2:07:46, 2:08:42 and 2:05:52. Cheruiyot's sub-2:06 brought that down last year, the gap was 1 minute (I don't know the wind conditions then though), but generally, it's 3 minutes or more (Yes, there are years where Boston is super slow, and there are years when it is much faster, but last year, the 2:05:52 was the first time ever that Boston was within a minute of the other races. So I don't think it's unreasonable to view Boston as slower)

Mutai vs Boston vs flat courses

This helps us understand where Mutai's performance ranks. If you believe Mutai is a 2:03:02 man in Boston, then you're either saying that hills don't affect him, or that he could be a 2:01 performer or better in London and Berlin! So we have something of a circular argument, it has to be said. If you believe that Mutai is genuinely 2:03:02 material, then you can dismiss the impact of the wind. But if you believe him to be a 2:05 runner, maybe 2:04:00 on the right day, then you have a wind impact of between 1 and 2 minutes COMPARED TO A FLAT COURSE. Now add the Boston "disadvantage" due to hills and the wind is again coming out to 2 to 4 minutes, depending on how much Mutai may have been affected by the hills.

The point is, it's not valid, under any circumstances, to compare Boston times to those of London or Berlin. Normally, it's for the opposite reason - Boston is slower. Today, it is the other way around, and that is significant because it helps us understand just how big an effect that tailwind might have had. In other words, the wind was at least sufficient to overcome a historical difference of 2 to 3 minutes on these other races.

But Boston is now a minute faster - the wind was responsible for overturning a 3 minute deficit and turning it into a 1 minute advantage. The wind is therefore estimated to be worth 4 minutes, based purely on historical averages (note that this approach assumes equality of strength of the races over the years, as well as the quality of the athletes at the top - I think this is a sound, valid assumption given the short three to five year period, others may disagree. Certainly, there was a time when Boston attracted "lesser" runners, but the last five years have been comparable to London, Chicago, Berlin)

If one makes the admittedly tenuous leap that Boston is around 2 to 3 minutes slower, then this 2:03:02 in Boston is worth a...better than a 2:01 in London. Only an extreme optimist would suggest this, and that's partly because we understand that such dramatic improvements don't happen, and because we know the characters. So next, we need to look at Mutai, Mosop, Hall and co and ask if these individuals are running "out of character"?

Within runners - an error-prone comparison, but valuable with interpretation

Comparing the same runner in two different events can be fraught with danger, but if you are sensible, there's valuable information there too. The reason for this is physiological variance - elite runners at this level can have bad days, where they are minutes off their best (Kebede in London may be an example of this. Cheruiyot yesterday is another). But when they have great days, they don't go minutes faster. If you are an elite (and by this, we're talking top 20 ever), you don't leap forward by minutes in one race. That happens to a Keitany, who has run a "slow" marathon in New York on debut, and then blasts 9 minutes faster in London. That's not that unexpected, given the context. But for the already established elite, there is such a thing as "acceptable physiological/performance variance".

So we accept the limitations, but use this to give more context to the physics and the history that we've already discussed.

Let's take Mutai. He has shown his marathon credentials on the fast, flat European races, first by running 2:04:55 in Rotterdam, and then 2:05:10 in Berlin. To improve by 1:53, on the toughest of the three courses, that's a huge improvement. And yes, runners have breakthrough days, but that margin is too large to simply be a "good day". At this level, once you're in the top 10 in history (which Mutai was even before today) improvements of 20 seconds are remarkable. Gebrselassie has set two world records, one by 29 seconds, the next by 26. Those are breakthroughs for this caliber of athlete.

1:53 is thus artificially high. So assume that Mutai was in the same condition as Rotterdam and Berlin, when he ran very close to 2:05 both times. Then, in Boston, he runs 2 minutes faster on a course that is normally about 2% slower than other courses. If you assume that Mutai was in great shape, 30 seconds faster than Rotterdam (a huge leap forward in performance), then you still have the wind helping him to the tune of 1:30 compared to a flat course...

Knowing your history and where Boston lies, you know have the worst case where you have to also add time for the Boston profile. 2 minutes? That's a conservative estimate based on history? Then suddenly you have between a three and four minute difference made by the wind. I suggested this in my first write-up after the race, and the physics calculations (assumptions and all) support the estimate - 2 to 3%, 3 to 4 minutes.

To return to the earlier example, if you believe the wind was worth only 1 minute today, then you're effectively saying that Mutai is a 2:04 guy in Boston, which means a 2:02 or better performer in London or Berlin (1 to 2% faster). Either that, or that he is "immune to hills".

The same is true for Ryan Hall. A 2:06:17 runner, Hall has raced the marathon numerous times. In his case, you have two Boston performances to compare to - a 2:09:40 and a 2:08:40. Maybe Hall continued his improvement and was in 2:08 or even 2:07:40 shape this year. He still ran a full 3 minutes faster than this.

Of course there is variability in performance. Athletes improve, they get worse. But by seconds, not minutes in this population, and a three minute improvement, suggests to me close to a 3-minute impact by the wind, if not more.

For an illustration from years gone by, the last time we had such strong tailwinds in Boston was 1994. That year, Cosmos Ndeti won the race in a course record that was bettered by only two men until this year (both Cheruiyots, one in 2006, and last year). Now there are four men going under 2:05 in one race.

But back in 1994, America's Bob Kempainen produced a "Beamonesque" performance by running 2:08:47, which was an American record at the time, and would remain so until Ryan Hall broke it. Kempainen was a good, but not great runner, and his next best time was 2:12:45. That's a 3:58 improvement, on the tougher Boston course, thanks to a windy day like we had today.

Yes, there are factors that influence this, which is why his numbers alone don't make this case. But when you have Boston's history, plus the comparison between Boston and other races, plus Mutai and Hall's recent racing credentials over Boston AND other courses, then a picture starts to come into focus.

The pacing and 2:03:02 performance in context

So how big an effect did the wind have? Impossible to say. Can we conclude that the wind was worth about 3 to 4 minutes? 2 to 3% I suspect so.

And so while Mutai's time is exceptional, I would interpret it differently. 2:03:02 is superb running - on the hills of Boston, wind or not, it defies belief. A second half of 61:05 is eye-popping. But if that wind is genuinely worth 2 to 3%, as I suspect, then the first half of 61:57 is actually worth about a mid-63 minute first half. In other words, conservative. That suddenly explains the searing pace in the second half, and it also helps us understand those final 10km.

The final 10km are also mostly downhill and so a 28:25 is extra-ordinary, but with a wind of even 2% (conservative), plus a relatively physiological "conservative" start, and the ingredients were there for a super fast finish, and an amazing overall time!

I guess we'll never know, but we have a great fall marathon season to look forward to!

The fall marathons and the impact of Boston

What will be fascinating is to see how this impacts the Fall marathons, particularly Berlin. It's like that Geoffrey Mutai will race there. Maybe even against Emmanuel Mutai. And Wanjiru. Will the elite men, having now touched the 2:03 barrier try to go out in 61:30 for the first half? That would be faster than Boston's first half, without the downhill start and the following wind, so it's adventurous, but does Boston 2011 change the mindset of the elite?

And if the top men, in a race, do go out in 61:30, or even 61:15, will that pace be sustainable? That's a fascinating question, and it sets the fall marathons up in a big way. Remember that until yesterday, only Haile Gebrselassie and Emmanuel Mutai had broken 62 for the second half of a major marathon. Now we have Geoffrey Mutai and Moses Mosop. Is that possible with a 61:30 first half? My initial thought is that a first half of 61:15 to 61:30 is just too quick, for now. 61:45, followed by a 62 min is doable, if the weather conditions are perfect in Berlin, perhaps.

But that's all conjecture - let's wait for October to see! Marathon running has never been healthier!

There are clearly differences in how the wind is assumed to impact performance! And our 2 to 3% conclusion in the post above, aided by the physics of some readers, seems to be on the conservative side! I suspect that this calculation is "idealized" and what you'll probably find is that the variable wind speed and direction in "real-world" Boston conditions, combined with shelter, combined with the different physical stature of runners, accounts for differences. But overall, I'm pretty confident (but never certain) in the estimation of 2 to 3%, or 3 to 4 minutes thanks to yesterday's wind in Boston.

Monday, April 18, 2011

Geoffrey Mutai has won the 2011 Boston Marathon, in the incredible time of 2:03:01. No, it's not a world record. It's not recognized because the course is downhill, point-to-point. And that means that the WR belongs to Haile Gebrselassie at 2:03:59, but this is an extra-ordinary time nonetheless.

Aided by the strong tailwind, Geoffrey Mutai of Kenya has scorched his way to a 2:03:02. Yep, you read that right, no typos here. 2:03:02. Incredible running, with a first half of 1:01:57 and a second half of 1:01:05. And that includes the Newton Hills. That shows the strength of the wind and also the incredible performance of Geoffrey Mutai.

In second was Moses Mosop, a marathon debutant, in 2:03:06, and third was NY champion Gebre Gebremariam, while Ryan Hall ran 2:04:58 to finish fourth.

The table below shows the splits. An absolutely extraordinary start and finish to the race. The first 10km were covered in 29:06, which was projecting 2:02:47. Then it actually slowed a little, the middle 20km being covered in 59:17, which is "only" 2:05 pace!

The final 10km are the real story though. 5km splits of 14:12 and then 14:13 saw Mutai break away, and then hold off a spirited Moses Mosop. That 10km stretch from 30km to 40km was therefore covered in 28:25, absolutely staggering running from the Kenyan who finished second in Berlin last year. I could scarcely believe the times, I've had to check it over and over...it brought the time down from a projected mid 2:04 to the 2:03:02 we ended up with. Amazing running, made all the more incredible when you bear in mind the Newton Hills, and that Boston does have a hilly second half.

How much did the wind give?

A word of caution though, not to dampen the mood...that was a mighty strong tailwind. The strength of the tailwind and its possible effects will be a talking point. How much advantage would it provide? And given that Boston is a hilly course (the Newton Hills), does the advantage provided by the win offset the disadvantage of those hills - remember, Boston's record has always been about 90 seconds to two minutes slower than that of London, Berlin, Rotterdam.

I'll give some thought to this question, and look at it in detail in a follow up post (once the dust has settled, or the "wind has died down", so to speak!). But it is telling that Moses Mosop was a 2:03:06 guy on debut and that Ryan Hall broke 2:05, almost four minutes faster than he's ever run on this course. And yes, people improve times, but 4 minutes? Even 1 minute for an established athlete at that level is enormous.

Geoffrey Mutai came into the race with a PB of 2:04:55, on the flat Rotterdam course last year. He improved it by 1:53. Hall meanwhile brought a PB of 2:06:17 into the race, and ran 1:19 faster, compared again to a flat course. So how much was that wind worth? Unless one believes that already-world class runners can knock 2 minutes off their best, then it's worth a great deal.

If I had to guess, I would say that the wind today was worth around two minutes, compared to a flat course with no wind. And three to four minutes faster than Boston on a still day. Remember, Boston is always about 2 to 3 minutes slower than the other major marathons of London, Berlin, Rotterdam. And so to be faster, that's not simply a great runner (or two - remember Mosop, only 4 seconds behind!).

So I'd estimate three for that reason, and because if you look at Hall and the women, they're running that much faster, and I'm afraid I don't believe in huge PBs for athletes who are already at that level. Keitany going much faster, yes, but that's a different situation. But as I said, I'll give it some thought and follow it up in another post!

Below are the splits from the race, and my race commentary. More to come, including some comments on the women's race. I just have some other commitments to attend to right now!

Join me tomorrow for more discussion - I'm sure it will be lively! And thanks for joining our marathon coverage!

Ross

Splits

Men's Race

Distance

Time

Interval time

Pace for interval

Projected time

5

14:29

14:29

2:54

2:02:13

10

29:08

14:37

2:55

2:02:47

15

43:45

14:39

2:56

2:03:04

20

58:43

14:58

3:00

2:03:53

Halfway

1:01:57

2:03:54

25

1:13:16

14:33

2:55

2:03:40

30

1:28:23

15:07

3:01

2:04:19

35

1:42:35

14:12

2:50

2:03:40

40

1:56:48

14:13

2:51

2:03:13

Finish

2:03:02

Women's Race

Distance

Time

Interval time

Pace for interval

Projected time

5

16:41

16:41

3:20

2:20:47

10

33:29

16:48

3:22

2:21:47

15

50:09

16:40

3:20

2:21:04

20

1:07:11

17:02

3:24

2:21:44

Halfway

1:10:52

2:21:44

25

1:24:15

17:04

3:25

2:22:12

30

1:41:49

17:34 (not Smith)

2:23:12

35

1:58:37

16:48

3:22

2:23:00

40

2:15:13

16:36

3:19

2:22:38

Finish

2:22:36

Race commentary

The men's race is off to the expected (and traditional) fast start. 14:29 through 5km and 29:08 through 10km means they're on course for something under 2:03. But before getting to excited, that's normal because the first 10km are downhill and very fast.

On the women's side, Kim Smith of New Zealand is well clear. Her 15 km time of 50:09 projects a 2:21, and she has a lead of 53 seconds. Interesting tactical game developing because Smith is not a rank outsider. It may be her first foray into the event, but her track pedigree is not the worst. So the main field are giving her some rope and allowing this large lead and it will be interesting to see how it unfolds. Certainly, 2:21 is not that quick - it will also slow down in the second half, so expect the pack to close down on her in time.

Men at approaching 15 km and Ryan Hall has gone ahead, he's only about 30 m clear and the pack (which is still very large) are behind watching. Nothing major will come of this, and Mutai has led the field back to Hall. The group was thinned by the move, and the pace is still very high, but the main protagonists are all there.

Men at 15km and the pace is still super fast. The time was 43:45, projecting a 2:03:04. For comparison, Robert Cheruiyot broke the record last year and they went through 15km in 44:48, so they're a full minute faster. This could be super fast if they just maintain it.

The field has bridged the gap to Hall and they've spread out over the road, about 12 men in the lead pack by my count. Hall has made a habit of running his own race in the past, and I guess it's a matter of opinion as to whether it works. It has brought some podium finishes, can it produce a win?

Kim Smith is through halfway in the women's race - 1:10:52, so she's slowed just a little. The gap is still large though, 50 seconds to the chase pack, a group that includes all the major protagonists including Kara Goucher and Dire Tune.

The men's race is now being pulled by record holder Robert Cheruiyot as we approach 20km. Mutai has been paying particularly close attention, whereas Gebre Gebremariam has remained "hidden" in the pack so far. The same was true in New York last year, he was barely mentioned until Central Park, when he was untouchable.

Hall is playing to the crowd as they run through Wellsley. Interesting. He held his hand to his ear, gave the crowd a "come on" in encouragement. He must be feeling pretty good at sub-2:04 pace...

Kim Smith at 25km, and the pace is slightly slower. 17:04 for the last 5km, following a 17:02 from 15km to 20km. That slight reduction has seen the chase pack close the gap a little. It's 46 seconds now, so it's inching down, but nothing dramatic just yet. Last year this time, there was a 58 second lead and that came down, but it was a different race then. The chase group is large, but doesn't include Kara Goucher, who has dropped off the chase pack.

The chase group are also within sight of Smith, the long straight roads don't help the breakaway, and so that group will just watch Smith, hold that gap and move in on her, probably when we get to the Newton Hills.

Men at halfway, and it's 1:01:54, and so the pace has slowed, though not by much. Hall is still being the aggressor, he's at the front, looking behind as if urging the group on. The group is still large, at this pace (it's almost a minute quicker than London yesterday).

Kim Smith has stopped. A right leg injury! And the defending champion Erkesso has dropped out, it sounds like - no splits at 15 or 20km. Kim Smith seemed to grab her right calf muscle and seems to be flinching. She's continued to run, but the main field is now much closer.

They'll close this gap quickly and once that happens, expect Smith to bail as well.

There is action on the men's side as well! Hall is gone from the lead pack and the group is strung out in a long line! Mutai is up there, Gebremariam is up there, and Hall is not. The attack was made by the Ethiopian Bekana Daba, who went to the front and glanced behind him repeatedly while ramping up the pace

That pace was fast enough to shed Hall and a host of others, including defending champ Cheruiyot. There are six men in the lead group now - Daba, Gebremariam, Mutai, Tola.

Kim Smith is caught and she has joined that lead group of women which is also six strong. Now it's five-strong, and Kim Smith is gone from the lead group. Her race is pretty much run now. Dire Tune is there, a former winner, and host of Kenyans. Names to follow...

The men's race is taking shape as they're near 25km. Apologies for the lack of split times - the website is not refreshing and the TV coverage is not showing times. But I can tell you that six men are in the lead group: Mutai, Gebremariam, Daba are there.

There is a lot of cagey running going on on the men's side. The six are all abreast and looking at one another. It's going fast then slow and this tactical game will cost time. The course record was looking under major threat, but if this continues, it may not continue. The 16th mile of the race was apparently 4:23 which is unbelievably fast - 2:43/km! That was responsible for the split in that big group, and it accounted for Hall and the defending champion. Hall is not done though - he is visible just off the back of the group.

1:21 into the men's race and now Mutai has come to the front. He's clearly strong and aggressive. Gebremariam is still in the group, which is interesting, he hasn't shown anything at all whereas Mutai is very prominent. As mentioned earlier, Gebremariam did the same in New York and timed his only move to perfection.

Also in this pack: Robert Kipchumba, Moses Mosop, Philip Sanga and Bekana Daba. Meanwhile, Ryan Hall is closing very gradually on the pack. That tells me that the pace of that group is slowing.

Things are hotting up on the women's side too. A surprise move by Desiree Davila at the front group, which is now 5 women. Four Kenyans and Davila.

It will be fascinating to see how Hall gets on in the men's race. The 5km from 20 to 25km was 14:33 and that was when the damage was done. Hall held the same pace, and now, as we head to 30km, the pace of the lead group has slowed and Hall has caught up again. He is therefore the barometer for the main pack - when they attack, he'll be gapped, and when they slow as a result of tactical games, he'll come back on.

Geoffrey Mutai is still the aggressor in the men's race, driving the pace on. It's a long line and so this is a big push. As anticipated, Hall is at the back of that line, and so you know the pace has increased. Hall's even pace is a good indication of the elite pace.

Desiree Davila is still there with the women, and they're down to three, as Alice Timbilil is dropped. It's an amazing performance from the American. The pace is holding firm - 16:50 for the last 5km and that's decent but not spectacular. Davila is being aggressive, not just sitting in, she's actually moving to the front and stretching the Kenyans. Caroline Kilel of Kenya is paying closest attention, with Sharon Cherop in third.

And Cherop seems stretched to me. Kilel is hanging in second, but it's Davila who is pushing the pace! They've just hit the two hour mark, I'm sorry I have no splits for you, but the TV coverage is very poor (at least it's there, I know...) This is about 20 minutes of running left, and the Kenyans are being challenged by a relatively unheralded Desiree Davila.

They're in a long line, the elastic being stretched by this move. This is a decisive 5 minutes in this race - if Davila can just sustain this pressure, she could do what few thought possible.

The men are at 30km, and the time there is 1:28:23. The last 5km have been run in 15:07, the slowest of the race but that's expected given the hills. The group is 8-strong. The projected time is 2:04:19, and so it's slowing down, but we may yet get that record. The last 5km of this race can be incredibly long though. Interesting finish developing.

Geoffrey Mutai is clear in the men's race. He's gone to the front and this is a decisive move. He's opened up what looks to be 10 seconds in next to no time! Are we going to see a second Mutai victory in one weekend? No relation, by the way, but the manner in which they're running the races is remarkably similar between this race and London yesterday!

Desiree Davila still has the two Kenyans for company. The commentator keeps calling her Dasilva. He says that the Kenyan with longer legs will have the advantage. Someone should tell that to Haile Gebrselassie - if height predicted performance, well...

The women's race is still together, three in that group, whereas the men's race has been fragmented by Mutai. He is making a big bid, a long way out.

There was a time about 10 minutes ago where it seemed that the Kenyans were under stress, but the front three are now together and much tighter, and Kilel looks particularly sprightly. Kilel is gone!

That's a big move, 2:11 into the race, and Kilel has made a big move, Cherop is following in second, but Davila is behind. She's trying to hang on, but the Kenyan surge has put her into some difficulty, for now.

Davila has now caught up! This is a great race among the women. Boston has produced some awesome women's races in recent years and this is building to be another one!

In the men's race, Mutai still has a small lead, but it seems to be shortening now. Hall is 57 seconds back, and the splits will be interesting to see later. Just a word on Mutai, his 5km split from 30 to 35 km was 14:12 - that's 2:50/km and an extra-ordinary move. That was what gave him the lead, but it's now slowly been reeled in by the chasing Moses Mosop.

2:16 in the women's race and Desiree Davila is still at the front, both Kenyans being towed along behind. Davila is stretching them - they may not be out of touch, but at this stage, you wouldn't be 5 m back of the leader if you could be 3m back and so the Kenyans are being challenged. This may well come down to a final sprint. Caroline Kilel is definitely looking the better of the Kenyans, but this is going to come down to a final sprint. Only about 6 minutes to go...

Mutai has now been joined by Mosop in the men's race, at 1:50. There are probably 15 minutes to go, they are on course for a huge course record. The tailwind has definitely done its job! Mosop is pushing on and these two will compete for first and second.

The Kenyans are back in front on the women's side. Davila is still there though, nothing decisive just yet. Davila has attacked. She's gone super hard with about 3 minutes to go! Kilel has responded and now counter-attacked, but Davila has dropped Cherop. Kilel has maybe 5 m on Davila!

Davila responds! Kilel responds! 300m to go, and this is amazing racing! Kilel has every answer though and she's finally subdued an amazing challenge from Desiree Davila. That was track racing between the women, and what a race.

The time is quick, as they come up to the finish line, it's going to be Caroline Kilel to win in 2:22:36 and about 2 seconds back, Desiree Davila of the USA, with Sharon Cherop in third. That was an epic finish!

To the men - about 7 minutes of running left as they're hitting 40km. It's Moses Mosop vs Geoffrey Mutai over 2km. Great, we get an advert break...

Men at 2:00 - Mutai and Mosop are together. It's Mosop in unchartered territory as this is his debut. Mutai is forcing the pace, but this too is not decisive. It will certainly be a new record, and we get to watch an interview with Davila, with only 3 minutes of the men's race. Great. What a genius director. I mean, could you guys not wait literally 4 minutes for this interview and let us see the men's finish? The mind boggles...

I can't believe that we'd take an interview with 3 minutes to run. Just wait 4 minutes...

The men are into the final few bends, and they're still locked together, side by side. They have made the left and now into the finish straight. It's a sprint for the line at what will surely be around world record time (though it can't be ratified, since it's a downhill course).

Mutai is in front, he's making the first big move and leads by 4 m. 5m. 10 m and it's going to be Mutai. He'll finish in under the world record time.

It's Geoffrey Mutai and the time is 2:03:01! Incredible!

Moses Mosop is second, a few seconds behind. And Gebre Gebremariam has finished third and Ryan Hall is fourth, a few seconds back of that.

Of course, it can't be a world record, but it does complicate marathon running for a while! It means we'll now always refer to "that other time, the unratified one" whenever we talk about the event!

But incredibly fast, and that's the power of that tailwind. It was predicted and the best athletes in the world have delivered on the promise of fast times in great conditions!

After yesterday's spectacularly fast London Marathon, there is more in store today as the rest of the world's elite hit Boston in the 115th running of the world's oldest annual marathon.

The weather forecasts for Boston give reason for optimism for fast times. Below is an image taken from this Letsrun article, and it shows that the forecast for Boston is about as good as one can possibly expect - cool, with a following wind that, because of Boston's point to point orientation, is basically from behind the whole way (click to enlarge)

That has led to speculation about what the elite field might be able to achieve, some even predicting a time faster than 2:03:59. It must be pointed out that this would not be recognized as a new world record, because of Boston's point to point course, but it may make for some spectacularly quick times, or splits at the very worst.

Last year in Boston, Robert Cheruiyot achieved what no one thought possible - a sub 2:06 clocking when he scorched the relatively tough course on route to a 2:05:52. It included an exceptional second half of 62:25 that includes the Newton Hills, and it was a performance that many suggested was worth something in the 2:03-range on one of the faster marathons around the world. You can read our recap of that race here, just to get in the mood for later.

I can't quite see a sub 2:04, regardless of wind, but if that tailwind does deliver, then we may well see a new course record, particularly given the strength of the field - in addition to Cheruiyot, there is Geoffrey Mutai and Gebre Gebremariam, two exceptionally strong runners, who I'd make favourites ahead of Cheruiyot. My picks would be Gebremariam to win, Mutai in second, with either Cheruiyot or debutant Moses Mosop in third.

The women's race was also exceptional last year, a real race to the line between Erkesso and Pushkareva. Last year Erkesso did a "Keitany", in that she went hard very early and built up a big lead. What she didn't do is hold it all the way, and Pushkareva almost caught her before losing out by 3 seconds in the final straight! Boston has in fact produced incredible races in the last few women's events, and this year should be no different.

As is now "tradition", we'll do a live post throughout the race, updating a table with splits and projected times, as well as 'play-by-play' commentary and thoughts from the race. So if for any reason you can't get to a TV, do join us later for coverage! (Assuming Universal Sports' feed works - it wouldn't be the first time I fail to see a marathon as a result of problem...but will do my best!)

Sunday, April 17, 2011

Emmanuel Mutai and Mary Keitany have won the 2011 London Marathon. Mutai shattered the course record in running 2:04:40, which makes him the fourth fastest man in history (with the 5th fastest performance), while Keitany broke 2:20 in her second run. For both, it was the manner in which the victory was achieved that was so impressive.

Men's race summary

The men's race, as is typical, was started with talk of a world record. That prospect seemed doomed as early as 15km, when the 5km split was 15:03. That was followed by another 15:03 up to 20km, and the pace was never as fast as had been promised.

Halfway was hit in 62:44, projecting a 2:05:28, which was fast, but even this was a little misleading because the first 5km had been so quick. Apart from those first 5km, the elite men were running closer to 2:06:30 pace. In fact, the section from 5km to 30km was run at 2:59.4/km, or 2:06:11 pace, so the fast first 5km and a truly exceptional final 10km were responsible for that time!

The race was really shaken up around 30km though. That's when Mutai hit the front, and the table below tells the story. He burned up the roads of London, running 5km splits of 14:26 and 14:19 between 30 and 40km. It was brutally fast, and no one was able to survive. Martin Lel fought bravely with Patrick Makau in second, but Mutai opened 20 seconds at 35km and was 53 seconds clear at 40km. The rest of the elite group was even more fragmented, pre-race favourite Kebede slipping over 2 minutes behind in this 10km stretch.

Mutai's final 12km were covered in 35:20, which is 2:54/km and 2:02 marathon pace! That surge was enough to bring the overall time down enormously, and contribute to a 61:56 second half, which was the only negative split of the elite men's race. Lel and Makau ran 63 minutes for the second half, everyone else was 64 minutes or longer. Admittedly, many will have shut off having seen the win go away, exaggerating these times slightly. So Mutai, who was second in London and New York last year, has gone one better by winning and a lot better by breaking 2:05 and joining a select group of marathon superstars.

Women's race summary

Keitany, meanwhile, exploded onto the marathon scene, having started in New York last year, she's now established herself as perhaps THE woman to beat. This is always the case when such a great half-marathon runner comes up, but the question mark is always whether they'll be able to translate their performances up. Keitany answered that question with a resounding yes today, running an exceptional second half to win in 2:19:19.

The women hit halfway in 1:10:37, which was fast, but gave no indication of what was to happen. It was pre-race Shobukhova who surged at halfway, but all that did was ignite Keitany, who went to the front and then never looked back. A 16:09, 16:01 and a 16:14 followed for the next three 5km splits, and the gap was over 1 minute.

Keitany slowed slightly at the end, and Shobukhova bravely clawed back some of the time she'd lost, finishing in a PB of 2:20:15. But it was an emphatic win for Keitany, who ran with such confidence. Her second half was an incredible 68:42, a massive negative split set up by the fast section from 20 to 35km. It also suggests more to come from Keitany, who must surely be capable of a sub-2:19, and it makes her the marathon runner to beat among the women. With London 2012 on the horizon, the rest of the world will be taking notice!

Below are the splits, and below those tables are my "in-race" thoughts, as the race developed in chronological order. As always, we'll be doing the same for Boston tomorrow, where ideal conditions should help set up another great race! So join us then!

Splits

Men's Race

Distance

Time

Interval time

Pace for interval

Projected time

5

14:34

14:34

2:55

2:02:56

10

29:23

14:49

2:58

2:03:59

15

44:26

15:03

3:01

2:04:59

20

59:29

15:03

3:01

2:05:30

Halfway

1:02:44

2:05:28

25

1:14:16

14:47

2:57

2:05:21

30

1:29:20

15:04

3:01

2:05:39

35

1:43:36

14:26

2:53

2:05:06

40

1:58:08

14:19

2:52

2:04:34

Finish

2:04:40

Women's Race

Distance

Time

Interval time

Pace for interval

Projected time

5

16:16

16:16

3:15

2:17:16

10

32:54

16:38

3:20

2:18:49

15

49:50

16:56

3:23

2:20:11

20

1:07:01

17:11

3:26

2:21:23

Halfway

1:10:37

2:21:14

25

1:23:10

16:09

3:14

2:20:22

30

1:39:11

16:01

3:12

2:19:30

35

1:55:25

16:14

3:15

2:19:19

40

2:12:07

16:42

3:20

2:19:22

Finish

2:19:19

In-race commentary time line

Women start

The women are running 5:15 to 5:20 per mile early on, which is a reasonable start - projects just under 2:20. But, they're just through 4km now, so a long way to go. The elite group is maybe 10 to 12 large. The commentator keeps saying that Keitany is running her first marathon - she's not. She came 3rd in New York last year. She's showing very aggressively at the front so far, but everyone is in touch.

5km in 16:16. 2:17 projected, so that's quick, but the start of London is slightly down (from 3km to 4km - the mile there was 5:05) so it's always reasonably quick. Expect it to slow down between 5km and 10km.

10km in 32:54, so it has slowed a little - 16:38 for the last 5km, including a slow mile of 5:48. Mikitenko dropped off just around 5km, but other than that, all the major contenders are there. Keitany running off to the side, Shobukova paying close attention to the pace-maker (and there is only one, which is strange)

Last mile in 5:02, so that must presumably be a downhill mile following the slight uphill. Either that or the pace is fast-slow, but that's less likely.

Men start

The men are about to start. What an incredible field. Makau vs Kebede is probably the big battle, Makau being the World # 1 last year, and Kebede being beaten only by Wanjiru in that epic Chicago race. But there are maybe 6 men with a good chance of winning. Martin Lel is the dangerous unknown - the most incredible racer in the marathon a few years ago, he's returning from injuries that have forced withdrawals from his last few races, so I don't expect, but hope for something from him.

At 15km, the women are on course for 2:20:11, so it is slowing. It's gone 3:15/km to 3:20/km to 3:23/km. The pacemaker has been joined by Shobukhova, who is probably more responsible for the pace than the official pacemaker. Very confident way to run. Keitany and Kiplagat, the big Kenyan challengers are in the pack now.

Men at 5km in 14:34. Very fast, projecting a 2:02, but don't get too excited - as we said for the women, the 4th kilometer is downhill so the first 5km are very quick. But it's a good sign of aggressive running so far. 17 men in the lead group, excluding 5 pacemakers.

The front men's group has now split, and of the five pacemakers, there are now only two in the front group. There was a plan for a second paced group to run for around 2:06 - 2:07 (compared to a 62 min through halfway for the first group), so they have now separated into the "hierarchies". There are nine in the group at the front, excluding those two pacemakers.

Women at 20km, and the progressive decline in speed has continued - the last 5km were at 3:26/km, so it's gotten slower by around 3sec/km since the start. The projection is now for 2:21:23, and given her finishing speed, this will suit Shobukhova nicely. Keitany may also enjoy the slower pace, given her half marathon credentials.

Shobukhova drives very hard through the halfway mark, which is reached in 1:10:37. That move didn't achieve too much, maybe she was just testing the Kenyans behind her. Very aggressive, that's a long way out to be driving at the front. She obviously feels good. Given how quick her finish is, it's a bit surprising to see that early push. The pacemaker is gone, so now it's a race.

Men at 10km, and it has slowed just a little, but that was expected. The last 5km were in 14:49, and the overall projected time is now 2:03:59, which happens to be the World Record. The 14:49 is a touch slower though, if they were to maintain that, they'll do just inside 2:05. The next 10km will tell us...

Mary Keitany has come to the front of the women's race now, and she's the big danger. Shobukhova's move has been the catalyst for an overall increase in the aggression of the race. The lead group is now seven, Keitany at the front and Shobukhova following her. Remember that Shobukhova ran the final 2.2km of Chicago faster than the men's winner did, so she has serious speed at the end of the marathon. A race between her and the half-marathon record holder is a great prospect!

Keitany is actually about 4 m clear. She's driving very hard. Shobukhova is gradually pulling the group back towards Keitany. It's all happening very early in the women's race. The 20-25km split will be very interesting. This pace is doing some serious damage to the group behind her, they're in a long line and gaps are appearing everywhere! She's surged again and opened a lead on Shobukhova.

Keitany has about 30 m on the chasers now. And Shobukhova is no longer doing the leading in the chase group. This is a serious move, it's opened the race up completely! This is the kind of racing not seenin women's marathon running.

At 25km, Keitany is six seconds clear. Her last 5km was in 16:09, the fastest of the race and that's what has done the damage. The group behind are split and this is the race's big move. Kiplagat is chasing, followed by Kebede, Bekele and Shobukhova, who started the racing at halfway and now being severely tested!

The men are at 15km in 44:26, having covered the last 5km in 15:03. That will disappoint the race organizers, having asked for a 62 at halfway. The pace is considerably slower than that now, and so any thoughts of the world record are fading fast.

Around 28km, and Shobukhova has moved into second, but Keitany has a gap of maybe 30 seconds. She's out of sight as they go through a twisty section and Keitany is looking superb, so fluid. The only danger for Keitany now is the distance and whether she'll pay for this surge. The pace hasn't slowed behind, and so Keitany is still holding a pace of around 3:15/km, which is incredible running. Last year's winning time was 2:21:59 by Shobukhova, this should be substantially faster.

Keitany has reached 30 km in 1:39:11, with a last 5km of 16:01, so she's actually gotten even faster! It's extra-ordinary front running. And while it's not entirely unchartered territory, to move this far out in only your second major marathon is exceptional running. The projected time has now dropped to 2:19:30, and the way Keitany is running, even 2:18 is not out of the question. The gap to the chasing Shobukhova & co is 33 seconds, and so they're running 16:25 for the last 5km, which is good pace, but Keitany is soaring at the front!

The men at 20km, and the pace is still pretty slow. 15:03 for the last 5km, and so that's 30:06 from 10km to 20km. And that's not what the agreed pace was. The halfway split is 62:44, and the commentators are projecting 2:05:30. That's a bit misleading, because the first 5km was so quick.

The truth is that given the last 10km, unless the pace picks up, they'll run around 2:06:20. Interesting to see how the racing in the second half affects this. Expect it to get quicker, but the sub 2:05 is looking out of reach for now. It'll take serious racing to bring them under that barrier.

All the main protagonists are there. Mo Trafeh has dropped off, 14 seconds down at halfway, but he was running above himself to be there, and now will try to settle one something around 2:07 pace. The lead group is 10 men, Makau, Kebede, Lel, Kwambai and Gharib are all still in that group.

Keitany has hit 35km, and the pace is still strong, though understandably has slowed somewhat. The last 5km were covered in 16:14. The lead has grown - Shobukhova and Kiplagat are now 1:09 behind, so she's opened up another 36 seconds in the last 5km! She's unlikely to be coming back and marathon running has a new star!

The men have increased the pace, and at 25km, they're speeding up again. The last 5km were in 14:47, which is 2:57/km pace and brings the projected time down. The group is still 10 deep, one pacemaker there. Kebede and Makau paying closer attention now.

Keitany through 40km in 2:12:07, so she has slowed - the last 5km has been covered at 3:20/km. The gap to Shobukhova, who is now clear in second, is 1:07, so that hasn't changed since the 35km mark (it was 1:09 then. She'll break 2:20 as well, comfortably - right now it's projected at 2:19:22, so expect 2:19:30-something.

The men are at 30km - 1:29:20, and it's just outside 15 for the last 5km. So again, slower than we all thought it would be. Martin Lel is still there, and looking so smooth. If his training was not quite geared towards London, it'll start to tell soon. But if he's there at 40km, then his finishing ability (assuming three years haven't eroded it) will be hard to match.

The race has now begun though, the pacemaker is gone and the big guns are to the front. The elite group is down to six men - Mutai, Kebede, Lel, Makau, dos Santos.

Keitany wins! 2:19:19! Women's marathon running has a new superstar! Whenever a super quick half-marathon athlete steps up, you expect great things, and Keitany is a fearsome half marathon athlete, so she is delivering on her promise now! She'll be a big favourite in London next year, and the rest of the world will have taken notice!

Shobukhova coming in second with a super quick finish, she'll run a PB in 2:20:15 and a great run, but put into the shade by an amazing performance from Mary Keitany.

And now we get to see the rest of the women finish while the men's race is being decided. This happens every year. Let's see who finishes 18th in the women's race, forget the men's winners...

The men's race is on! Mutai is pushing the pace and it's Martin Lel following! Lel is there, and challenging. Kebede is in third, Makau in fourth, but gapped from the front three just slightly, and we're coming up to 35 km.

No wait, we're going to see the women again. We'll wait for Jo Pavey, I'm sure. I appreciate the local interest, of course, but this is a lot like having a car dealership and putting the Ferraris and Porsches in the back, with the Toyotas and Volkswagens out front. This is a global event, they need to cater to it - you can't grow the sport by "hiding" the superstars. Very ordinary.

Ok, she's done now for the love of marathon running, can we PLEASE see the men's race! No? Ok, let's stick with the 20th best women for a little longer, and NOT watch the men... London, you have truly outdone yourself this year.

Oh, there is a men's race after all. They're at 35km, and Emmanuel Mutai is clear. He covered the last 5km in 14:26, an exceptional surge in pace. That was enough to drop Lel, who was "last man standing", and Mutai is 20 seconds clear! That gap was created very quickly - at 32 km, they were together, and so Lel may have hit something of a wall.

This is the race's decisive move, with mile splits of 4:30 and 4:31 (2:47 per kilometer for 3km). Lel is second, 20 seconds down at 35km, and Makau a second back of him. The pre-race favourite, Tsegay Kebede, who spoke a good game of a world record before the race, has been pushed right back. At 35km, he's 36 seconds down in 5th place. In fourth is Dos Santos of Brazil, but we'll get a much clearer picture at 40km in a few minutes' time.

From the camera shots, no one will catch Mutai, he has clear road behind and ahead, and he'll win this race with about 12 minutes to go. Meanwhile, we'll switch back to the women, and watch the women finishing in 2:38 or slower. And we'll stay with these pictures, to see a 2:41 marathon runner, while the elite men running 2:05 are ignored. Go London coverage! It's not difficult to split the feeds, the international feed can easily be separated from what is shown locally.

Mutai at 40km, and the time is 1:58:05, and Mutai is flying! He's going to break the course record, and run one of the fastest marathons in history! And that's off the back of a relatively conservative period from 5km to 30km - 62:44 at halfway, and the section 5km to 30km was run at 2:06:11 pace. So Mutai is going to go under 62 minutes for the second half!

Exceptional running! Martin Lel has hung in there and is second, 53 seconds down, with Makau just behind him in third. Makau will probably catch him. That means that Lel and Makau have maintained the pace and are on course for around 2:05:30, which is exactly what the halfway split predicted. So Mutai has been the man to emerge from the pack today with an outrageously fast second half. His last 5km were covered in 14:19, following on from a 14:26, and that's 2:52/km.

Mutai has won in 2:04:40, making him the fourth fastest man in history, behind Gebrselassie, Kibet and Kwambai (Geb has run faster twice, incidentally). It's a course record, and it's been achieved with a second half of 61:56, which is super quick. The final 12km, incidentally, from 30km, were covered in 35:20, which is 2:54 pace, or a 2:02 marathon!

Martin Lel has won a sprint for second in 2:05:45, and that is an exceptional comeback from the multiple London champion. Makau is third only a second behind, and dos Santos has finished fourth. Tsegay Kebede, meanwhile, has finished fifth in 2:07:47. That's pretty disappointing for him, given the pre-race talk and his last few performances. It's made more so by the fact that the halfway split of 62:44 was not that quick, so his second half was 65:03, which he'll be disappointed with. A bad day at the office.

The pacing - only one faster second half

An interesting note on pacing - the halfway split was reached in 62:44, which predicts at 2:05:28. And so the only elite athlete in the race to negative split was Mutai. That's unusual, but what's more amazing is the size of his negative split, compared to the positive split in some of the other elites.

For example, Mutai's difference was 62:44 - 61:56, a 48 second differential faster! Lel and Makau ran the second half in 62:51, so 7 seconds slower. dos Santos was 63:50 or 66 seconds slower, and Kebede ran his second half 2:19 slower (65:03 vs 62:44).
So a race of attrition for all but the top 3, and especially for Mutai, who aided by his final 12km in 2:54/km was absolutely exceptional. The large spread across the top 8 was the result of Mutai's amazing surge, combined with a big drop-off in pace by almost everyone else. One would not have thought that the men finishing in 5th or lower would run 65 minutes for the second half...

Jonathan Dugas, PhDCurrent residence:Chicago, USAEmployment: Director of Clinical Development, The Vitality GroupResearch interests: Temperature regulation and exercise performance, with a special emphasis on how fluid ingestion affects those two things. In addition, the effects of exercise on health improvement and risk modification in large populationsSports interests: Cycling, running, triathlon, endurance sports

Full discolusre:The views expressed on this site are not those of the University of Cape Town (UCT), the Sports Science Institute of SA (SSISA), The Vitality Group, or Discovery Holdings.